This specification relates to data communications.
Conventionally, to synchronize data transmissions between a transmitter and receiver, a reference clock signal may be transmitted with a data signal. In general, growth in bandwidth in modern data transmission follows a logarithm law, and network and point-to-point connections favor high-speed data transfers without a reference clock signal.
During high-speed data transfers jitters may be created that contaminate the signal being transferred. A re-timer may be used to clean jitters and synchronize data transmissions. Conventionally, to synchronize data transmissions without communicating a reference clock signal, a narrow frequency offset between the transmitter and receiver may be used. For example, in a passive optical network (PON), a clean local reference is generated at a receiver to synchronize the received data, but the difference between the transmitter frequency and receiver frequency is limited to 200 ppm (part-per-million). Due to the limited bandwidths, multi-protocols and multi-data rates data transmissions cannot be achieved with this conventional approach.